Charging query

[tonyiiiafl]

On my 1994 390CPMY 454’s, When underway, if I run the house battery, the house battery charges by showing 14.0 +/- volts on The starboard engine gauge at the helm. The port shows 12.7. Now if I switch over, the port shows 14.0=/- and the starboard shows 12.7. When I leave it on both to cruise then BOTH gauges show 14.0 =/- volts. Upon reaching my destination, both batteries are fully charged. is this normal or should both charge. I checked the selector switch unit her stairs and all appears not to have been mucked with. SO, what I have done is run with switch on both, and then switch to the house when I shut down engines. ??

[bud37]

Yup that is exactly how they are wired....normal for that system ....you start the engines with the start batteries then switch to both while running, then back to house with engines off. I would also have it in the start position for when using the windlass. That is exactly how I used our system ....requires some manual switching but at least it keeps you aware of the state of your batteries.

[tonyiiiafl]

GREAT news, as I was a wondering if that was going to be my next project....unf%$k another previous owner shoddy stuff.

[Viper]

Ya unfortunately that's a consequence of how the DC system is wired using a selector switch, that's one of the reasons why I don't like that setup. It can be changed though with a little work.

[km1125]

You can add a "voltage sensing relay" between the batteries, so when one is being charged it will connect to the other one and apply a charge to that one too. When there is no longer a charge available (from any source) it will disconnect between the batteries so you don't run them both down if you continue to have a load on.

[g36]

Those charging relays are very handy